I am running Vista Ultimate.  It doesn't have that limitation.  For instance, when I run Carrara with nothing else but mandatory drivers etc. running, I am usually using about 3.1GB of actual RAM for Carrara, not counting the page file.  I have an enhanced task manager that shows me all kinds of neat little info bits.  CPU Time, Page Faults, memory etc...

www.sysinternals.com is where you get it.  It's called Process Explorer.  Try it out.  It can be set to replace the normal task manager.